Hematology and Oncology Pharmacology Flashcards
heparin–mechanism
lowers the activity of thrombin and factor Xa
short half life
heparin–use
immediate anticoagulation for pulmonary embolism (PE), acute coronary syndrome, MI, deep vein thrombosis (DVT),
used during pregnancy–does not cross placenta
follow PTT
heparin–toxicity
bleeding
thrombocytopenia (HIT)
osteoporosis
drug-drug interactions
heparin–antidote
use protamine sulfate–positively charged mc that binds negatively to heparin
what are the advantages/disadvantages to using low molecular weight heparins?
low molecular weight heparins–enoxaparin, dalteparin
advantages:
act more on factor Xa
have better bioavailability
2-4 times longer half life
can be administered subcutaneously and w/o lab monitoring
disadvantage:
not easily reversible
explain heparin induced thrombocytopenia (HIT)
development of IgG antibodies against heparin bound platelet factor 4 (PF4)
antibody heparin PF4 complex activates platelets –> thrombosis and thrombocytopenia
name the direct thrombin inhibitor
bivalirudin–related to hirudin, the anticoagulant used by leeches
direct thrombin inhibitor–mechanism
directly inhibits activity of free and clot-associated thrombin
direct thrombin inhibitor–use
venous thromboembolism
atrial fibrillation
can be used in HIT
doe not require lab monitoring
direct thrombin inhibitors–toxicity
bleeding
antidote for direct thrombin inhibitors
no specific reversal agent
can attempt to use activated prothrombin complex concentrates (PCC) and/or fibrinolytics (eg. transexamic acid)
warfarin–mechanism
interferes with gamma carboxylation of vitamin K dependent clotting factors II, VII, IX, X, and proteins C and S
metabolism affected by polymorphisms in the gene for vitamin K epoxide reductase complex (VKORCI)
in lab–effect on EXtrinsic pathway and inc PT, long half life
“the EX-President went to WAR(farin).”
warfarin–use
chronic anticoagulation–venous thromboembolism prophylaxis and prevention of stroke in atrial fibrillation
follow PT/INR
can warfarin be used in pregnant women? why?
no, b/c crosses placenta (unlike heparin)
warfarin–toxicity
- bleeding
- teratogenic
- skin/tissue necrosis
- drug-drug interactions
- proteins C and S have shorter half lives than clotting factors II, VII, IX, X which results in early transient hypercoagulability with warfarin use
- skin/tissue necrosis within first few days of large doses believed to be due ot small vessel microthromboses
antidote for warfarin
vitamin K
how would you rapidly reverse warfarin?
fresh frozen plasma
explain heparin “bridging”
- heparin frequently used when starting warfarin
- heparin’s activation of antithrombin enables anticoagulation during initial, transient hypercoagulable state caused by warfarin
- initial heparin therapy reduces risk of recurrent venous thromboembolism and skin/tissue necrosis
compare and contrast heparin vs. warfarin
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name direct factor Xa inhibitors
ApiXaban
rivatoXaban
direct factor Xa inhibitors–mechanism
bind to and directly inhibit factor Xa
direct factor Xa inhibitors–use
- treatment and prophylaxis for DVT and PE (rivaroxaban)
- prophylaxis in patients with atrial fibrillation
- oral agents do not require coagulation monitoring
direct factor Xa inhibitors–toxicity
bleeding–no reversal agent is available
name the thrombolytics
Alteplase (tPA)
Reteplase (rPA)
streptokinase
tenecteplase (TNK-tPA)
thrombolytics–mechanism
- directly or indirectly aid conversion of plasminogen to plasmin, which cleaves thrombin and fibrin clots
- inc PT
- inc PTT
- no change in platelet count
thrombolytics–use
- early MI
- early ischemic stroke
- direct thrombolysis of severe PE
thrombolytics–toxicity
- bleeding
when are thrombolytics contraindicated?
- patients with:
- active bleeding
- history of intracranial bleeding
- recent surgery
- known bleeding diatheses
- severe hypertension
how to treat toxicity of thrombolytics
- aminocaproic acid, an inhibiotr or fibrinolysis
- can also use fresh frozen plasma and cryoprecipitate to correct factor deficiencies
name the ADP receptor inhibitors
clopidogrel
prasugrel
ticagrelor (reversible)
ticlopidine
ADP receptor inhibitors–mechanism
- inhibit platelet aggregation by irreversibly blocking ADP receptors
- prevent expression of glycoproteins IIb/IIIa on platelet surface
ADP receptor inhibitors–use
- acute coronary syndrome
- coronary stenting
- decrease incidence or recurrence of thrombotic stroke
ADP receptor inhibitors–toxicity
- neutropenia (ticlopidine)
- TTP may be seen
cilostazol, dipyridamole–mechanism
- phosphodiesterase III inhibitor
- inc cAMP in platelets
- results in inhibition of platelet aggregation
- vasodilators
cilostazol, dipyridamole–use
- intermittent claudication
- coronary vasdilation
- prevention of stroke or TIAs (combined with aspirin)
- angina prophylaxis
cilostazol, dipyridamole–toxicity
- nausea
- headache
- facial flushing
- hypotension
- abdominal pain
name the glycoprotein IIb/IIIa inhibitors
- abciximab
- eptifibatide
- tirofiban
glycoprotein IIb/IIIa inhibitors–mechanism
- bind to the glycoprotein receptor IIb/IIIa on activated platelets
- prevent aggregation
what is abciximab made from?
(glycoprotein IIb/IIIa inhibitors)
monoclonal antibody Fab fragments
glycoprotein IIb/IIIa inhibitors–use
- unstable angina
- percutaneous transluminal coronary angioplasty
glycoprotein IIb/IIIa inhibitors–toxicity
- bleeding
- thrombocytopenia
what are the anti-metabolite drugs?
- azathiprine and 6-mercaptopurine
- cladribine
- cytarabine
- 5-fluorouracil
- methotrexate
azathiprine, 6-mercaptopurine–mechanism
- purine analogs –> dec de novo purine synthesis
- activated by HGPRT
- azathioprine is metabolized into 6-MP
azathiprine, 6-mercaptopurine–use
- prevent organ rejection
- rheumatoid arthritis
- IBD
SLE - used to wean patients off steroids in chronic dz and to treat steroid refractory chronic disease
azathiprine, 6-mercaptopurine–toxicity
- myelosuppression
- GI
- liver
how are azathiprine and 6-mercaptopurine metabolized, and how does this affect toxicity?
- they are metabolized by xanthine oxidase
- so, they have inc toxicity with allopurinol or febuxostat
cladribine–mechanism
- purine analog
- multiple mechanisms–inhibition of DNA polymerase, DNA strand breaks
cladribine–use
- hairy cell leukemia
cladribine–toxicity
- myelosuppression
- nephrotoxicity
- neurotoxicity
cytarabine (arabinofuranosyl cytidine)–mechanism
- pyrimidine analog
- inhibition of DNA polymerase
cytarabine (arabinofuranosyl cytidine)–use
- leukemias (AML)
- lymphomase
cytarabine (arabinofuranosyl cytidine)–toxicity
- myelosuppression with megaloblastic anemia
- CYTarabine causes panCYTopenia
5-fluorouracil–mechanism
- pyrimidine analog bioactivated to 5-FdUMP–covalently complexes folic acid
- this complex inhibits thymidylate synthase –> dec dTMP –> dec DNA synthesis
5-fluorouracil–use
- colon cancer
- pancreatic cancer
- basal cell carcinoma (topical)
- effects enhanced with the addition of leucovorin
5-fluorouracil–toxicity
- myelosuppression
- worsened with addition of leucovorin (folinic acid)
methotrexate–mechanism
- folic acid analog–competitively inhibits dihydrofolate reductase –> dec dTMP –> dec DNA synthesis
methotrexate–use
- cancers:
- leukemias (ALL)
- lymphomas
- choriocarcinoma
- sarcomas
- non-neoplastic:
- ectopic pregnancy
- medical abortion (with misoprostol)
- rheumatoid arthritis
- psoriasis
- IBD
- vasculitis
methotrexate–toxicity
- myelosuppression
- reversible with leucovorin “rescue”
- hepatotoxicity
- mucositis (ie. mouth ulcers)
- pulmonary fibrosis
name the antitumor antibiotics
- bleomycin
- dantinomycin (antinomycin D)
- doxorubicin, daunorubicin
bleomycin–mechanism
induces free radical formation –> breaks in DNA strands
bleomycin–use
- testicular cancer
- Hodgkin lymphoma
bleomycin–toxicity
- pulmonary fibrosis
- skin hyperpigmentation
- minimal myelosuppression
dactinomycin (actinomycin D)–mechanism
intercalates in DNA
dactinomycin (ACTinomycin D)–use
- Wilms tumor
- Ewing sarcoma
- rhabdomyosarcoma
- used for childhood tumors
- “children ACT out”
dactinomycin (actinomycin D)–toxicity
myelosuppression
doxorubicin, daunorubicin–mechanism
- generate free radicals
- intercalate in DNA –> breaks in DNA –> dec replication
doxorubicin, daunorubicin–use
- solid tumors
- leukemias
- lymphomas
doxorubicin, daunorubicin–toxicity
- cardiotoxicity (dilated cardiomyopathy)
- myelosuppression
- alopecia
what can be used to prevent cardiotoxicity that may result from using doxorubicin, daunorubicin?
dexrazoxane–iron chelating agent
name the alkylating agents
- busulfan
- cyclophosphamide, ifosfamide
- nitrosoureas
- carmustine
- lomustine
- semustine
- streptozocin
busulfan–mechanism
crosslinks DNA
busulfan–use
- CML
- also used to ablate patient’s bone marrow before bone marrow transplantation
busulfan–toxicity
- severe myelosuppression–in almost all cases
- pulmonary fibrosis
- hyperpigmentation
cyclophosphamide, ifosfamide–mechanism
- cross link DNA at guanine N-7
- require bioactivation by the liver
cyclophosphamide, ifosfamide–use
- solid tumors
- leukemia
- lymphomas
cyclophosphamide, ifosfamide–toxicity
- myelosuppression
- hemorrhagic cystitis
how can you prevent hemorrhagic cystitis that may result from using cyclophosphamide, ifosfamide?
- prevented by using mesna (thiol group of mesna binds toxic metabolites) or N acetylcysteine
nitrosoureas–mechanism
- requires bioactivation
- cross blood brain barrier –> CNS
- cross link DNA
nitrosoureas–use
brain tumors–including glioblastoma multiforme
nitrosoureas–toxicity
- CNS toxicity
- convulsions
- dizziness
- ataxia
name the microtubule inhibitors
- paclitaxel, other taxols
- vincristine, vinblastine
paclitaxel, other taxols–mechanism
- hyperstabilize polymerized microtubules in M phase so that mitotic spindle cannot break down
- anaphase cannot occur
paclitaxel, other taxols–use
- ovarian carcinomas
- breast carcinomas
paclitaxel, other taxols–toxicity
- myelosuppression
- neuropathy
- hypersensitivity
vincristine, vinblastine–mechanism
- vinca alkaloids that bind beta tubulin and inhibit its polymerization into microtubules –> prevent mitotic spindle formation
- M phase arrest
vincristine, vinblastine–use
- solid tumors
- leukemias
- Hodgkin (vinblastine) lymphomas
- non Hodgkin (vincristine) lymphomas
vincristine, vinblastine–toxicity
- vincristine
- neurotoxicity–areflexia, peripheral neuritis
- consipation–including paralytic ileus
cisplatin, carboplatin–mechanism
cross link DNA
cisplatin, carboplatin–use
- testicular carcinomas
- bladder carcinomas
- ovary carcinomas
- lung carcinomas
cisplatin, carboplatin–toxicity
- nephrotoxicity
- peripheral neuropathy
- ototoxicity
how would you prevent nephrotoxicity that may result from use of cisplatin, carboplatin?
- use amifostine (free radical scavenger) and chloride (saline) diuresis
etoposide, teniposide–mechanism
eTOPOside inhibits topoisomerase II –> inc DNA degradation
etoposide, teniposide–use
- solid tumors
- particularly testicular and small cell lung cancer
- leukemias
- lymphomas
etoposide, teniposide–toxicity
- myelosuppression
- alopecia
Irinotecan, topotecan–mechanism
- inhibits topoisomerase I
- prevents DNA unwinding and replication
Irinotecan, topotecan–use
- colon cancer (irinotecan)
- ovarian and small cell lung cancers (topotecan)
Irinotecan, topotecan–toxicity
- severe myelosuppression
- diarrhea
hydroxyurea–mechanism
inhibits ribonucleotide reductase –> dec DNA Synthesis (S phase specific)
hydroxyurea–use
- melanoma
- CML
- sickle cell disease (inc HbF)
hydroxyurea–toxicity
severe myelosuppression
prednisone, prednisolone–mechanism
- various
- bind intracytoplasmic steroid receptor
- alter gene transcription
prednisone, prednisolone–use
- most commonly used as glucocorticoids in cancer chemotherapy
- used in CLL, non Hodgkin lymphomas
- part of combination chemotherapy regimen
- used as immunosuppressants
- ie. in autoimmune diseases
prednisone, prednisolone–toxicity
- cushing like symptoms
- weight gain
- central obesity
- muscle breakdown
- cataracts
- acne
- osteoporosis
- HTN
- peptic ulcers
- hyperglycemia
- psychosis
bevacizumab–mechanism
- monoclonal antibody against VEGF
- inhibits angiogenesis
bevacizumab–use
- solid tumors
- colorectal cancer
- renal cell carcinoma
bevacizumab–toxicity
- hemorrhage
- blood clots
- impaired wound healing
erlotinib–mechanism
- EGFR tyrosine kinase inhibitor
erlotinib–use
- non small cell lung carcinoma
erlotinib–toxicity
- rash
cetuximab–mechanism
- monoclonal antibody against EGFR
cetuximab–use
- stage IV colorectal cancer–wild type KRAS
- head and neck cancer
cetuximab–toxicity
- rash
- elevated LFTs
- diarrhea
imatinib–mechanism
- tyrosine kinase inhibitor of BCR-ABL
- Philadelphia chromosome fusion gene in CML
- c-kit
- common in GI stromal tumors
imatinib–use
- CML
- GI stromal tumors
imatinib–toxicity
- fluid retention
rituximab–mechanism
- monoclonal antibody against CD20
- found on most B cell neoplasms
rituximab–use
- non Hodgkin lymphoma
- CLL
- ITP
- rheumatoid arthritis
rituximab–toxicity
- inc risk of progressive multifocal leukoencephalopathy
tamoxifen, raloxifene–mechanism
- selective estrogen receptor modulators (SERMs)
- receptor antagonists in breast
- receptor agonists in bone
- block the binding of estrogen in ER + cells
tamoxifen, raloxifene–use
- breast cancer treatment (tamoxifen only) and prevention
- raloxidene also used to prevent osteoporosis
tamoxifen, raloxifene–toxicity
- both drugs increase risk of thromboembolic events (ie. DVT, PE)
tamoxifen–toxicity
- partial agonist in endometrium
- inc the risk of endometrial cancer
- causes hot flashes
raloxifene–toxicity
- no in in endometrial carcinoma b/c it is an estrogen receptor antagonist in endometrial tissue
trastuzumab (herceptin)–mechanism
- monoclonal antibody against HER-2 (c-erbB2)–a tyrosine kinase receptor
- helps kill cancer cells that overexpress HER-2 through inhibition of HER2-initiated cellular signaling and antibody dependent cytotoxicity
trastuzumab (herceptin)–use
HER-2 + breast cancer and gastric cancer
(trans2zumab)
trastuzumab (herceptin)–toxicity
- cardiotoxicity
- HEARTceptin damages the heart
vemurafenib–mechanism
- small molecule inhibitor of BRAF oncogene + melanoma
- VEmuRAF-enib is for V600E-mutated BRAF inhibition
vemurafenib–use
- metastatic melanoma
know the common chemotoxicities of the following:
- Cisplatin/Carboplatin
- Vincristine
- Bleomycin, Busulfan
- Doxorubicin
- Trastuzumab
- Cisplatin/Carboplatin
- CYclophosphamide
- 5-FU
- 6-MP
- Methotrexate
- Cisplatin/Carboplatin –> ototoxicity (and nephrotoxicity)
- Vincristine –> peripheral neuropathy
- Bleomycin, Busulfan –> pulmonary fibrosis
- Doxorubicin –> cardiotoxicity
- Trastuzumab –> cardiotoxicity
- Cisplatin/Carboplatin –> nephrotoxic (and acoustic nerve damage)
- CYclophosphamide –> hemorrhage cystitis
- 5-FU –> myelosuppression
- 6-MP –> myelosuppression
- Methotrexate –> myelosuppression
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